Traditionally, electrical Transmission and Distribution (T&D) has been accomplished using Alternating Current (AC) currents and voltages. Interruption of AC currents typically takes advantage of the periodic zero-crossing that is inherent with AC waveforms. The AC circuit breaker clears the current at or near the point where the AC current crosses the zero-current line.
Direct current (DC) power has recently become much more important in the power T&D arena. A challenge encountered with the use of DC power is that DC current, lacking the natural zero-crossing, is much more difficult to interrupt. For example, M. Mobarrez et al., “Comparative study of DC circuit breakers using realtime simulations,” IECON 2014—40th Annual Conference of the IEEE Industrial Electronics Society, Oct. 29, 2014-Nov. 1, 2014, pgs. 3736-3742, which is fully incorporated by reference, provides an in-depth look at current state-of-the-art technologies for interrupting DC current and the challenges associated with present technologies.
New systems that are based on DC require a simple, effective, means for active interruption of DC currents for normal circuit switching and for the interruption of fault currents. Circuit breakers based on the technology described herein overcome challenges presently encountered in the art, some of which are described above, and provide a solution to interruption of DC that is not presently available.